I get that sometimes. Have you tried actually crying? I don't know if you are a male or female, but crying helps me. Watch something sad or sentimental and just try to cry, it helps to ease anxiety and that agitated and on-edge feeling.
i have it alllllll the time only when i think about it or i am scared anxious or feeling down it makes me so mad i cry but it dosent go away i have to get up and walk around and get the fact into me its all in my head and it actually works 9 times out of 10 hope it helps to no you are far from alone x